Field of the Invention
The invention lies in the field of nuclear power generation. More specifically, the invention pertains to a core barrel for a reactor pressure vessel of a nuclear reactor plant and to a method for repairing a core barrel. Such core barrels are known, for example, from AEG-Telefunken-Handbuch [AEG-Telefunken manual], Vol. 10, "Siedewasserreaktoren fur Kernkraftwerke" ["Boiling Water Reactors for Nuclear Power Plants"], Andrej Sauer, Berlin 1969, p. 100, or from U.S. Pat. No. 4,038,136 to Gallet et al. Those prior art core barrels are essentially cylindrical containers which are supported on the shell of the reactor pressure vessel, on bearings or projections, and which carry the reactor core.
During operation, particularly in boiling water reactor plants, the core barrel--disposed in the reactor pressure vessel of a nuclear reactor plant for the purpose of receiving the reactor core--may be damaged at the weld seams located on its shroud. Although the loads acting on the weld seams are slight during normal operation, higher loads may occur in the event of design basis accidents, and these loads have to be safely eliminated in order to preserve the shutdown capability and the intactness of the core internals. It is necessary, in particular, to prevent a situation where a weld seam on the shroud of the core barrel (core shroud) ruptures completely resulting in the risk that the core grid could shift.